ONE million Australian cardholders who are still using their signature to complete a transaction face being left unable to pay from next week.

More than 800,000 payment terminals around the nation are in the process of being upgraded in a move designed to boost security for consumers and prevent fraud.

From August 1, cardholders will be prohibited from using their signature to complete a transaction.

The payment industry’s PINwise campaign spokeswoman Nicole Pedersen-McKinnon said many cardholders have left it to the eleventh hour to obtain a four-digit personal identification number and those who hadn’t should do so immediately.

“From August 1 there will be no signature safety net so you will need a PIN to purchase, it’s now only a matter of days away so it’s really time to act,’’ she says.

“There are more than 1 million people who are habitually signing; that’s a pretty high number given we are only a few days away from the transition to PIN only.

“If you are trying to trying to transact with a card without a PIN from August 1 you do run the risk of not being able to complete your purchase unless you have cash or another card you can use.”

Latest industry figures show about 80 per cent of Australian cardholders are regularly using a PIN to pay but the remainder are yet to ditch the pen.

MasterCard’s vice president of public policy and corporate affairs Brent Thomas said using a PIN was much safer for consumers.

“We know not all merchants check the signature at the point of sale so by using a PIN you know for certain the machine is checking your PIN,’’ he said.

“Like any new habit once you have used your PIN two or three times it becomes second nature.”

There will be no change to the way consumers pay using contactless payments or online transactions, but in some cases when using a card issued from overseas the signature will still be used to verify the transaction.

Cardholders yet to switch to PIN are being urged to contact their financial institution immediately.

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